Voltage-gated ion channels play a critical role in the electrical activity of neuronal and muscle cells. Large families of voltage-gated ion channels (e.g., sodium channels) have been identified. These ion channels have been the target of significant pharmacologic study, due to their potential role in a variety of pathological conditions. Biophysical and pharmacological studies have identified the sodium channel isoforms NaV1.3, NaV1.7, NaV1.8, and NaV1.9 as particularly important in the pathophysiology of pain, in particular neuropathic pain. Recently, gain-of-function mutations in SCN9A, the gene which encodes NaV1.7, have been linked to two human-inherited pain syndromes, inherited erythromelalgia and paroxysmal extreme pain disorder, while loss-of-function mutations in SCN9A have been linked to complete insensitivity to pain. Dib-Hajj et al, Pain Medicine 10(7):1260-1269 (2009) (abstract). Pain conditions affect approximately 100 million U.S. adults at a cost of $560-635 billion annually in direct medical treatment costs and lost productivity. Relieving Pain in America, National Academies Press, Washington, D.C. (2011), page 2. Unfortunately, current treatment options typically provide only partial pain relief, and are limited by inconvenient dosing and by side effects, such as somnolence, ataxia, edema, gastrointestinal discomfort and respiratory depression. Therefore, novel compounds are desirable to address the shortcomings of presently available treatment options.